In effect, it could be said that Heart of Darkness is set entirely on the River Thames, being a tale within a tale recounted upon a yawl making its way down the English river.

The second longest river in the United Kingdom, the Thames links several towns and cities in southern England, but is best known for flowing through central London. By the 18th century, the Thames was already one of the world's busiest waterways, due to London's position at the centre of the vast, mercantile British Empire. The advent of the railways during the Victorian era reduced commercial activity on the river, but it was not until the growth of road transport and the decline of the Empire, in the years following 1914, that the economic prominence of the Thames was significantly reduced.

Although never actually named, Conrad's 'sepulchral city' is clearly Brussels, the capital of Belgium.

The Congo Free State was administered directly from King Leopold II’s Royal Palace, or from the Brussels offices of subsidiary companies such as Albert Thys’ Compagnie du Congo pour le Commerce et l'Industrie.

Marlow's interview at the Company's headquarters mirrors Conrad's own experience with the Société Anonyme Belge pour le Commerce du Haut-Congo. He was interviewed by the managing director, Albert Thys, at the Société’s main offices in the city’s Brederodestraat.

The deepest river in the world, the second largest by volume of water discharged, and the ninth longest with an overall length of 4,700 km (2,920 miles), the Congo River and its tributaries flow through the Congo rainforest, the second largest in the world.

The novel’s shadowy African setting of ivory grabbing ‘pilgrims' was none other than the Congo Free State, where Conrad spent six months in 1890 as an employee of the Belgian trading company, the Société Anonyme Belge pour le Commerce du Haut-Congo.

In existence between 1885 and 1908, the Congo Free State was the private colony of King Leopold II of Belgium, a vast area of Central Africa which included the entire area of the present Democratic Republic of the Congo (formerly Zaire). For three decades, the Belgian monarch ruled the area as his own personal fiefdom, accruing vast profits through the ruthless exploitation of the territory’s natural resources and its people. His reign lasted until 1908, when growing international outrage at the atrocities committed against indigenous people forced him to cede the colony to the Belgian state. It was renamed the Belgian Congo.

The sea-reach of the Thames is that part of the Thames Estuary where the river (see Setting) meets the waters of the North Sea. Its western boundary is generally defined as being near Canvey Island on the Essex shore, with its eastern boundary running from North Foreland in Kent to Harwich in Essex.

In his Author’s Note for The Secret Agent (1907), Conrad offers a more ambivalent description of ‘the biggest, and the greatest town, on earth’, describing London as:

a monstrous town more populous than some continents and in its man-made might as if indifferent to heaven’s frowns and smiles; a cruel devourer of the world’s light. There was room enough there to place any story, depth there for any passion, variety there for any setting, darkness enough to bury five million of lives.

Deptford, Greenwich and Erith were important docks on the River Thames.

Deptford is located on the south bank of the Thames, on the eastern edge of London. Greenwich is immediately east of Deptford. Erith is eight miles further east. All three docks were established by Henry VIII, but Deptford – site of the first Royal Dockyard – was undoubtedly of greatest importance: for much of the period during which Britain ruled the waves, her ships were built there.

Founded in 1565 by Sir Thomas Gresham as a centre of commerce for the city, the Exchange provided a forum for the transactions of London merchants and traders whose business dealings had previously been conducted in the street or in crowded shops and stores.

The Chapman lighthouse was a screw-pile lighthouse which stood off the coast of Canvey Island in the Thames Estuary from 1851 to 1957, warning sailors away from the area’s numerous mud flats. Designed by the engineer James Walker, the lighthouse was built on the water supported by seven legs (it may have looked like three legs from a distance as described in the novel) so that waves could pass underneath the construction without major resistance. It was eventually demolished after falling into a state of disrepair.

On 9 August 1877, the celebrated explorer Henry Morton Stanley became the first white man to trace the course of the Congo River to the sea, solving one of the last great mysteries of African exploration. Within two years the explorer would return to the Congo, this time in the employ of King Leopold II of Belgium, to lay the foundations for what would become the Congo Free State.

Conrad was interviewed at 13 rue de Bréderode, Brussels, for his job with the Société Anonyme Belge. Reflecting the company’s close ties with King Leopold, the building was situated immediately behind the Royal Palace, from where the Belgian monarch oversaw his vast business interests in the Congo Free State.

Gran’ Bassam (Grand-Bassam) is a city in Côte d'Ivoire (Ivory Coast), east of Abidjan. It was the French colonial capital from 1893 until 1896, when the administration was transferred to Bingerville. The city remained a key seaport until the growth of Abidjan from the 1930s.

Little Popo is the former name of Aného, a town in southeastern Togo. It became the capital of the German colony of Togoland in 1880, but quickly declined in importance after the capital was transferred to Lomé in 1897.

Originally the man-of-war was a sail-propelled, heavily-armed warship which first emerged during the 16th century. By the mid-17th century, the man-of-war had developed into the ship of the line, dominating the seas for the next 200 years before it was superseded by the ironclad warship during the latter half of the 19th century.

In common usage, the term man-of-war continued to refer generally to any large warship belonging to the navy of a recognised government.

During the conflict with Dahomey (see following bookmark), the French primarily employed gunboats, a type of military vessel designed specifically for the bombardment of coastal targets; though it was a French cruiser, the Seigneley, Conrad claimed to have witnessed shelling a native camp hidden in the jungle near Grand-Popo. This would have been part of the French blockade of the Kingdom of Dahomey that began on 4 April 1890.

The seat of the government of the Congo Free State was at this time the port town of Boma, which lies on the Congo River around 100 km from Muanda, where the river meets the Atlantic Ocean. Boma served as the capital of the Congo Free State and Belgian Congo from 1886 until 1926, when the capital was moved to Leopoldville (since renamed Kinshasa).

In the original manuscript Conrad had offered a much fuller description of Boma:

We went up some twenty miles and anchored off the seat of the government. I had heard enough in Europe about its advanced state of civilization: the papers, nay the very paper vendors in the sepulchral city were boasting about the steam tramway and the hotel – especially the hotel. I beheld the wonder. It was like a symbol at the gate. It stood alone, a grey high cube of iron with two tiers of galleries outside towering above one of those ruinous-looking foreshores you come upon at home in out-of-the-way places where refuse is thrown out. To make the resemblance complete it wanted only a drooping post bearing a board with the legend: rubbish shot here, and the symbol would have had the clearness of the naked truth …

The passage was excised presumably because Conrad did not want to include any suggestion of economic or structural development in the colony that could be used as mitigation for the various crimes of the colonial enterprise.

These rapids are the Yellala Falls, a series of waterfalls and cataracts on the Congo River just upstream from Matadi, and the lowest of a long series of rapids, known as the Livingstone Falls, that render the river unnavigable for over 300 km. Before the completion of the Matadi-Leopoldville railway, the 230-mile journey to the next navigable point on the river at Stanley Pool (now known as Pool Malebo) had to be undertaken by foot.

This is Matadi, the port town founded by Henry Morton Stanley in 1879. Situated on the left bank of the Congo River, 148 km from the mouth and about 8 km below the rapids that make the river impassable for a long stretch, it remains the chief sea port of the Democratic Republic of the Congo.

After spending two weeks in Matadi, Conrad and a caravan of thirty-two men began their 230-mile journey by land to Kinshasa. They followed an established trail, which became the route of the railway, through the Pataballa Mountains to Congo de Lamba. On July 8 they arrived in Manyanga, where they stopped to rest for two weeks. By July 27 they had taken a detour to visit the Mission of Sutili, before continuing to Luasi and then on to Kinfumu. Conrad reached Nselemba on August 1, and presumably Kinshasa, fifteen miles away, on August 2.

In Conrad's Western World (1971), Norman Sherry suggests Conrad took much longer than he should have done on the journey from Matadi to Kinshasa: the journey could be done in seventeen days; Conrad completed it in thirty-five days.

Zanzibaris were used extensively as mercenaries throughout Africa. They were often employed by the Congo Free State as soldiers and policemen, primarily because they were thought to demonstrate more discipline than other African tribes.

Page 40.
" I came in sight of the big river again, and hobbled into the Central Station "

The Central Station is based on Kinshasa, the post established in 1883 by Stanley five miles upriver from Leopoldville. Over time the two settlements grew and merged into the city that was to become the capital of the Belgian Congo in 1923 – called Leopoldville by the Belgians and Kinshasa today.

Kurtz's station is loosely based on Stanley Falls, founded in 1883 by Stanley as the Congo Free State's first trading post in the area. After subsequent Belgian colonisation of the area, it grew into the settlement of Stanleyville (present day Kisangani), which remains the major centre of the northern Congo.

In contrast to the fictional station, Stanley Falls was already a permanent settlement by 1890, with offices, warehouses, workers’ quarters, vegetable plantations, a jail and a hospital.